Track clamp for hoists



Jan. 23, 1962 w. E. RICHTER 3,017,958

TRACK CLAMP FOR HOISTS Filed Dec. 11, 1958 6 Sheets-Sheet 1 L e 2:21 21 Walter E. Hchzer Kin Maw HIT-777E Jan. 23, 1962 w. E. RICHTER TRACK CLAMP FOR HOISTS e Sheets-Sheet z Filed Dec. 11, 1958 Walter E. Eicfizer Jan. 23, 1962 w. E. RICHTER 3,017,958

TRACK CLAMP FOR HOISTS Filed Dec. 11, 1958 6 Sheets-Sheet 3 Wu [fer 1 mam Jan. 23, 1962 w. E. RICHTER TRACK CLAMP FOR HOISTS 6 Sheets-Sheet 4 Filed Dec. 11, 1958 Jan. 23, 1962 w. E. RICHTER TRACK CLAMP FOR HOISTS 6 Sheets-Sheet 5 Filed Dec. 11, 1958 r w w m E 5 a w H Jan. 23, 1962 w. E. RICHTER TRACK CLAMP FOR I-IOISTS 6 Sheets-Sheet 6 Filed Dec. 11. 1958 United States Patent 3,017,958 TRACK CLAMP FOR HOISTS Walter E. Richter, Muskegon, Micl1., assignor to Manning, Maxwell & Moore, Inc, Muskegon, Mich., a corporation of New York Filed Dec. 11, 1958. Ser. No. 779,754 6 Claims. (Cl. 18843) This invention relates to improvements in a track clamp for hoists, and more particularly to a track clamp highly desirable for use in connection with a trolley hoist either of the push-pull type or the hand geared type, the clamp functioning to anchor the hoist in a desired position along its track and retain the hoist against movement for any desired period of time, although the invention will have other uses and purposes as will be apparent to one skilled in the art.

In the past a number of types of track clamps suitable for use with traveling hoists and the like have been developed, but in each instance of. which I am aware, these formerly known track camps' were objectionable for various reasons. For example, many of them failed to provide, at least in a ready and eflicient manner, adequate clamping force in the horizontal direction, they added load to the hoist trolley wheels and were not self supporting and self aligning, in some instances they tended to induce bending stress in the hoist trol'ey frame or side plates thereof, in many cases'the addition of the clamping element prevented the hoist trolley and clamp from readily negotiating curves of small radius in the track, in some instances they were not feasible for use as a self-locking clamp, and in most cases were objectionably unwieldy and expensive.

With the foregoing in mind, it is an important object of the instant invention to provide a track clamp of the character set forth herein which readily, easily, and efiiciently provides firm and positive clamping of the track on which a hoist trolley rides.

Another object of the instant invention is the provision of an economical form of track clamp capabe of providing a clamping force in the horizontal direction of at least /3 the rated load of the trolley hoist with which the clamp may be associated.

Also a feature of this invention is the provision of a track clamp of the character set forth herein which is self supporting and which is capable of aligning itse f with a trolley or the like with which it may be associated.

Still another object of the instant invention is the provision of a track clamp capable of association with a trolley hoist. and which clamp adds no load to the hoist trolley wheels.

A further feature of the track clamp of this invention resides in the fact that it carries its own track wheels to support itself and maintain alignment with a trolley with which it is associated or connected.

Also a feature of the instant invention resides in the provision of a track clamp connectable to the trolley of a hoist or the like, and which is so constructed that it will not tend to induce any bending in the hoist trolley frame or side plates.

The invention also seeks the provision of a track clamp of the character set forth herein which may be pivotally connected to a trolley, in such a manner that both the clamp and trolley can readily negotiate curves of very small radius in the track which the trolley rides.

Still another object of the invention is the provision of a track clamp that may readily be utilized as a self-locking or dead man clamp.

Still another feature of the instant invention resides in the provision of a self-locking track clamp having means embodied therewith to eliminate chattering in the event "ice the clamp is suddenly released under a relatively heavy load.

While some of the more salient features, characteristics and advantages of the instant invention have been above pointed out, others will become apparent from the following disclosures, taken in conjunction with the accompanying drawings, in which FIGURE 1 is a fragmentary side elevational view of a trolley hoist on an overhead track, showing the same equipped with a track clamp embodying the principles of the instant invention;

FIGURE 2 is an enlarged fragmentary, part sectional, part elevational View taken substantially as indicated by the line 11-11 of FIGURE 1;

FIGURE 3 is a fragmentary side elevational view of a track clamp embodying principles of the instant invention, but of a slightly different construction, illustrating how the same may be connected to a trolley hoist;

FIGURE 4 is a fragmentary part vertical sectional, part elevational view taken substantially as indicated by the line IV IV of FIGURE 3;

FIGURE 5 is a fragmentary side elevational' view of a track clamp embodying principles of the instant invention but of a still different construction, illustrating how the same may be connected to a trolley hoist or the like;

FIGURE 6 is a fragmentary plan sectional view, taken substantially as indicated by the line VIVI of FIGURE 5; and

FIGURE 7 is a side elevational view of one of the track clamping members embodied in all illustrated forms of the instant invention, and its supporting means.

As shown on the drawings:

Referring to FIGURE 1, it will be seen that the first embodiment of the instant invention is shown connected in operative relationship to an integrated trolley hoist which is movable along an overhead track 1 in the form of an I-beam. The trolley comprises a pair of side plates 2, only one of which is illustrated, disposed on opposite sides of the track and each side plate carries a pair of wheels 33 which ride the lower flange of the track 1. Secured to the trolley, as by bolts 4 and 5, is the hoist frame or casing generally indicated by numeral 6 which contains any suitable form of hoisting mechanism and with which is associated a lifting chain 7 carrying a load hook 8. The hoisting mechanism is operated in or contro'led in any suitable manner, such as by a hand chain, a pendant control, or the equivalent depending upon the type of hoist.

The track clamp embodies a pair of allochiral channel shaped arms 9 and 10. The side flanges of the arm 9 cmbrace the adjacent end of the head 11 of a T shaped member 12 (FIGURE 1), and the arm is pivoted to that head 11 in an intermediate location by means of a pivot pin or bolt 13 which passes through the side flanges of the arm. The arm 10 is similarly pivoted to the opposite end of the head 11 by means of a bolt 14 as seen in FIG URE 2.

The arms 9 and 10 are identical, and at the upper end thereof each carries a wheel 15 on a fixed shaft 16, which wheel rides the lower flange of the I-beam track 1, the wheels, of course, being disposed on opposite sides of the track web. Opposite the side edge of the bottom flange of the track, each arm carries a clamping shoe 17 mounted on a. fixed threaded shaft 18. Now with reference to FIGURE 7 of the drawings, it will be seen that each clamping shoe, which is preferably made o-f'metal, has a knurled or otherwise embossed clamping face 19 for firm engagement with the edge of the track flange. The clamping shoe is rotatably mounted on a reducedand grooved end 20 of the threaded shaft 18 by means of a pin 21. The threaded shaft 18, of course, permits a proper adjustment of the clamping shoe so that the track clamp may be used with various sizes of track flanges.

Now referring again to FIGURE 2, it will be seen that an internally threaded cross head block 22 is pinned as at 23 to the lower end of each of the arms 9 and 10. A shaft 24 has oppositely threaded portions 25 and 26 engaged in the blocks 22-22, so that rotation of the shaft 24 causes the lower ends of the arms 9 and to move toward or away from each other depending upon the direction of rotation of the shaft. One end of the shaft is keyed as at 27 to a hand wheel 28 operated by a suitable hand chain 29 by means of which an operator may control the track clamp.

The track clamp is connected to the trolley of the hoist by means of a pin 30 which extends through the side plates of the trolley, as seen best in FIGURE 1. This pin is shimmed as indicated at 31 in FIGURE 2 so that it may be adjusted to accommodate various sizes or spacings between the side plates of the trolley. The pin may be locked in position by cotter pins as illustrated or in other suitable manners, and is free to rotate relatively to the trolley side plates. Welded to this pin at diametrically opposed locations are forwardly extending plates 32 and 33, and a drilled circular boss 34 integral with the rear end of the T-shaped member 12 is disposed between those plates. The plates are also drilled to accommodate a vertical pivot pin 35 around which the track clamp may pivot laterally relatively to the hoist trolley.

In operation, the instant trolley clamp is extremely simple but highly effective. During movement of the hoist along the track 1 from one location to another, the track clamp merely leads or follows the hoist trolley as the case may be, riding upon its own wheels, whereby the clamp is both self supporting and self aligning with the hoist trolley, and adds no load to the hoist trolley wheels, nor does it impose any bending stresses upon the hoist trolley. The clamp may pivot vertically, if necessary, relatively to the trolley on the pin 30, and by virtue of the pivoting around the pin 35, the clamp and trolley can both readily negotiate track curves of extremely small radius. When it is desired to hold the lhoist trolley in a certain location, it is simply necessary for the operator to pull the hand chain 29 and rotate the shaft 24 to spread the lower ends of the clamp arms 9 and 10, thus causing the clamp shoes 1717 to firmly engage the side edges of the track flange. That engagement is so strong with the present structure that the clamp will pass all prescribed government tests and will exert a resistive clamping force of at least /3 of the rated load capacity of the hoist. The clamp will remain locked in position holding the hoist trolley stationary until the hand chain 29 is actuated in the reverse direction to release the clamping shoes.

The form of the invention seen in FIGURES 3 and 4 functions substantially the same and is of substantially the same construction as that above described, but is provided with means to make the track clamp self locking. The same clamp arms 9 and 10 and the same actuating arrangement therefor, as above described, is utilized in the embodiment of FIGURES 3 and 4, and the track clamp is connected to the hoist trolley in the same manner as above described.

However, as seen best in FIGURE 4, the shaft 24 which actuates the clamp arms 9 and 10 is provided with an enlarged central portion 36 between the oppositely threaded portions 25 and 26. Around this enlarged portion 36 of the shaft is disposed a relatively strong coil spring 37, one end of which is secured to the shaft as indicated at 38, and the other end of which is pinned to the arm 9 as indicated at 39. This spring is so arranged that it tends to rotate the shaft 24 in a direction to spread the lower ends of the arms 9 and 10 and thus cause clamping engagement of the shoes 17l7 with the side edges of the track flange. With this arrangement, therefore, it is necessary for the operator to pull the hand chain 29 in order to release the track clamp, and when the operator releases the chain the spring 37 takes over and the clamp immediately engages the track.

It has been found in some instances, such as when there is a load on the hoist, and the track has an inclination and the hand chain 29 was suddenly released after the trolley acquired some acceleration, chattering of the track clamp might occur. Under such circumstances, the sudden engaging of the track flange by the clamping shoes under a heavy load would cause a turning action on the clamp which would momentarily release the clamp and then it would immediately engage the track flange again, thus producing chattering.

With that in mind, means have been provided to eliminate any such chattering, although in the great majority of cases, such means would not be necessary. The illustrated embodiment of these means comprises a pair of upstanding brackets 40 and 41 welded or equivalently secured to the head 11 of the T-shaped member 12, in spaced relationship to each other. As seen in FIGURES 3 and 4, the brackets 40 and 41 are disposed so as to underlie the bottom flange of the I-beam track 1. Each of the brackets 40 and 41 carries a wheel 42 at each end thereof which is disposed just beneath the bottom flange of the track, and in sufficient proximity to the track so that either the forward or rear pair of wheels may contact the track upon a tendency of the clamp to chatter. Preferably, these wheels do not actually roll on the track during normal operation.

Except for the diflerences above pointed out, the embodiment of the invention seen in FIGURES 3 and 4 operates and possesses all of the advantages above discussed in connection with the embodiment of FIGURES 1 and 2, although this second embodiment is in the form of a dead man or self-locking clamp.

The embodiment of the instant invention seen in FIGURES 5 and 6 operates upon the same principle as the previously described embodiments, but is constructed so as to occupy less headroom, and is made somewhat more rugged. In this instance, the clamp arms pivot about vertical pivot pins, swinging in a horizontal plane, instead of swinging through a vertical plane about horizontal pivots as in the previously described embodiments.

In this embodiment of the invention, substantially L- shaped clamp arms 43 and 44 are utilized and disposed with the long leg of the L horizontal. These arms are intermediately pivoted as indicated at 45 and 46, respectively, to the transverse head 47 of a T-shaped link 48, as seen best in FIGURE 6. The pivot pins 45 and 46 are vertically disposed, each passing through botlr flanges of the respective channel-shaped arm and the head 47 of the link 48. The shorter leg of each arm, namely the leg extending vertically, carries a clamping shoe 17 with its adjustable shaft 18 of the same kind as previously described. On the same leg above the clamping shoe, each arm also carries a wheel assembly 1516 of the same character above described, which wheels ride on the upper face of the lower flange of the I-beam track 1.

At the free ends of the longer legs of the arms 43 and 44, trunnion blocks 49 and 50, respectively, are pinned to the arms. These trunnion blocks are apertured and internally threaded to accommodate reversely threaded portions 51 and 52 of the clamp control shaft 53. As in the previous embodiments, rotation of the shaft in one direction causes the shoes 1717 to engage the edge of the track flange, and rotation of the shaft 53 in the other direction releases such clamping engagement. This shaft may be selectively rotated in either direction by means of a hand wheel 54 and hand chain 55.

This embodiment of the invention is connected pivotally with a hoist trolley or other piece of equipment in substantially the same manner as the previous embodiments, by means of a pin 55 to diametrally opposite regions of which upper and lower plates 56 and 57 are welded or equivalently secured. The T-shaped link 48 is provided with an arcuate head 58 on the rear end thereof, pivotally connected between the plates 56 and 57 by a vertical pin 59. This arrangement gives the track clamp assembly substantially universal movement relatively to the hoist trolley or other mechanism with which it may be connected, whereby both the track clamp and hoist trolley may negotiate track curves of small radius.

From the foregoing, it will be noted that all embodiments of the instant invention herein set forth are economical in construction, rugged and highly durable, provide more than suflicient clamping force against the track, have substantially universal movement relatively to the trolley or other assembly with which they may be connected, may be either of the self-locking or manual locking type, and are self supporting and self aligning as well as occupying a minimum space.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a track clamp, a connecting link having a transverse head, an arm pivoted at an intermediate point to each end of said head, confronting clamp shoes carried by said arms on one side of the pivot points, track wheels carried by said arms on the same side of the pivot points, and means to selectively separate or move toward each other the ends of said arms on the opposite side of the pivot points, connecting means for connecting the clamp to a mechanism travelling the same track, and a vertical pivot pin joining said connecting means to said link.

2. In a track clamp assembly, intermediate arm spacing means, a pair of confronting arms intermediately pivoted to said means at spaced points, a track riding wheel on one end of each arm, a clamp shoe on each arm between the respective wheel and pivot point, a nut secured to the other end of each arm, a control shaft having reversely threaded portions engaged with said nuts, and actuating means for rotating said shaft in either direction.

3. In a track clamp assembly, intermediate arm spacing means, a pair of confronting arms intermediately pivoted to said means at spaced points, a track riding wheel on one end of each arm, a clamp shoe on each arm between the respective wheel and pivot point, resilient means tending to move the other ends of said arms away from each other to maintain said shoes in track clamping position, and control means for moving said other arm ends toward each other against the action of said resilient means to release the clamp.

4. In a track clamp assembly, a pair of wheels to ride a track, a clamping assembly including clamping shoes to selectively engage said track suspended from said wheels, a pivot shaft for engagement with another mechanism riding the same track, a plate secured to said shaft and projecting therefrom, a link extending from said clamping assembly, and a pivot pin disposed at right angles to said pivot shaft and joining said link and plate.

5. In a track clamp assembly, supporting means, track riding wheels on said means and from which the clamp assembly depends, opposed track clamping shoes on said means, control means operable to move said clamping shoes into engaged and released positions relatively to the track, an adjustable stationary shaft supporting each said shoe .to compensate for varying track dimensions, and each shoe being mounted for rotation on its shaft end.

6. In a track clamp assembly, inter-mediate arm spacing means, vertical pivot pins carried by said means in spaced relationship, a pair of spaced confronting L-shaped arms each having its longer and horizontal leg connected to one of said pivot pins, a track riding wheel on the shorter and vertical leg of each said arm, a track clamp shoe on each said arm below the respective wheel, and control means for moving the ends of the arms beyond the pivot pins toward and away from each other in a horizontal plane.

References Cited in the file of this patent UNITED STATES PATENTS 1,177,707 Jones Apr. 4, 1916 1,572,941 McBride Feb. 16, 1926 1,972,367 Willard Sept. 4, 1934 2,268,302 Pringle et a1. Dec. 30, 1941 FOREIGN PATENTS 27,430 Great Britain of 1909 

